Shifting system for human-powered vehicle

ABSTRACT

A shifting system for a human-powered vehicle comprises a controller. The controller is configured to receive a driving torque and a cadence of the human-powered vehicle from at least one sensor. The controller is configured to determine a permitted shift timing based on the driving torque and the cadence. The controller is further configured to control a shift mechanism to perform a gear shift during the permitted shift timing in accordance with a permitted cadence range and a first threshold of the driving torque.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/295,555, filed Mar. 7, 2019 and entitled SHIFTING SYSTEM FORHUMAN-POWERED VEHICLE, the disclosure of which is hereby incorporated byreference in its entirety for all purposes.

BACKGROUND

Many human-powered vehicles such as bicycles include the ability toshift gears. If a rider of such a vehicle inputs a gear shift command ata poor timing for shifting, then an ideal shifting point on the sprocketcan be missed. In this case, shift shock may occur and cause the riderdiscomfort. While very experienced riders may develop skills for timingthe gear shift to avoid shift shock, many other riders lack such skills.

SUMMARY

In accordance with a first aspect of the present invention, a shiftingsystem for a human-powered vehicle comprises a controller. Thecontroller is configured to receive a cadence of the human-poweredvehicle from at least one sensor. The controller is configured tocontrol a shift mechanism to perform a gear shift in accordance with apermitted cadence range.

With the shifting system according to the first aspect, it is possibleto restrict the gear shift to be performed during the permitted cadencerange, thereby improving shift performance.

In accordance with a second aspect of the present invention, theshifting system according to the first aspect is configured in a mannersuch that the controller is configured to output a command signal forthe gear shift to the shift mechanism if the cadence is within thepermitted cadence range.

With the shifting system according to the second aspect, it is possibleto allow the gear shift to be performed during the permitted cadencerange, thereby improving shift performance.

In accordance with a third aspect of the present invention, the shiftingsystem according to the first or second aspect is configured in a mannersuch that the controller is configured to refrain from outputting thecommand signal to the shift mechanism if the cadence is determined to beoutside the permitted cadence range.

With the shifting system according to the third aspect, it is possibleto prevent the gear shift from being performed outside the permittedcadence range, thereby improving shift performance.

In accordance with a fourth aspect of the present invention, theshifting system according to any one of the first through third aspectsis configured in a manner such that the controller is configured toreceive a driving torque of the human-powered vehicle from at least onesensor.

With the shifting system according to the fourth aspect, it is possibleto control the gear shift to be performed in view of the driving torque,thereby improving shift performance.

In accordance with a fifth aspect of the present invention, the shiftingsystem according to the fourth aspect is configured in a manner suchthat the controller is configured to determine a permitted shift timingbased on the driving torque and the cadence.

With the shifting system according to the fifth aspect, it is possibleto it is possible to restrict the gear shift to be performed during thepermitted shift timing, thereby improving shift performance.

In accordance with a sixth aspect of the present invention, the shiftingsystem according to the fifth aspect is configured in a manner such thatthe permitted shift timing includes a first timing interval that has afirst start and a first end. The controller is configured to control theshift mechanism to perform the gear shift by determining at least one ofan estimated travel distance of the shift mechanism and estimated travelspeed of the shift mechanism for performing the gear shift, calculatingan estimated duration of time that is required for performing the gearshift based on at least one of the estimated travel distance and theestimated travel speed, determining that the gear shift can be commencedafter the first start of the first timing interval and completed priorto the first end of the first timing interval, and outputting thecommand signal to the shift mechanism based on the determination result.

With the shifting system according to the sixth aspect, it is possibleto avoid beginning a gear shift that will end after the permitted shifttiming, thereby improving shift performance.

In accordance with a seventh aspect of the present invention, theshifting system according to the sixth aspect is configured in a mannersuch that the estimated travel speed is calculated based on the cadenceand the travel distance.

With the shifting system according to the seventh aspect, it is possibleto estimate the travel speed without providing means to directly measurethe travel speed.

In accordance with an eighth aspect of the present invention, theshifting system according to the sixth aspect is configured in a mannersuch that the gear shift is one of a plurality of gear shifts, theestimated travel distance is one of a plurality of estimated traveldistances, and the estimated travel speed is one of a plurality ofestimated travel speeds. The controller is configured to store a mapthat maps each of the plurality of the gear shifts to an associated oneof the plurality of the estimated travel distances and one of theplurality of the estimated travel speeds in a memory. The controller isfurther configured to determine the at least one of the estimated traveldistance and the estimated travel speed for performing the gear shift atleast in part by using the map to identify at least one of the estimatedtravel distance and the estimated travel speed associated with the gearshift.

With the shifting system according to the eighth aspect, it is possibleto provide a map of values in advance, thereby shortening the processingtime to determine whether the gear shift can be performed within thepermitted shift timing.

In accordance with a ninth aspect of the present invention, the shiftingsystem according to the sixth aspect further comprises the shiftmechanism including a rear derailleur having a rear chain guideconfigured for lateral movement over the estimated travel distance in adirection parallel to a rotational axis of a rear sprocket assemblyhaving a plurality of rear sprockets to urge a chain from the one of therear sprockets to the other of the rear sprockets in the gear shift.

With the shifting system according to the ninth aspect, it is possibleto improve shift performance in a rear derailleur.

In accordance with a tenth aspect of the present invention, the shiftingsystem according to the sixth aspect further comprises the shiftmechanism including a front derailleur having a front chain guideconfigured for lateral movement over the estimated travel distance in adirection parallel to a rotational axis of a front sprocket assemblyhaving a plurality of front sprockets to urge a chain from the one ofthe front sprockets to the other of the front sprockets in the gearshift.

With the shifting system according to the tenth aspect, it is possibleto improve shift performance in a front derailleur.

In accordance with an eleventh aspect of the present invention, ashifting system for a human-powered vehicle comprises a controller. Thecontroller is configured to receive a driving torque of thehuman-powered vehicle from at least one sensor. The controller isconfigured to control a shift mechanism to perform a gear shift inaccordance with a first threshold.

With the shifting system according to the eleventh aspect, it ispossible to restrict the gear shift to be performed in accordance withthe first threshold, thereby improving shift performance.

In accordance with a twelfth aspect of the present invention, theshifting system according to the eleventh aspect is configured in amanner such that the controller is configured to output a command signalfor the gear shift to the shift mechanism if the driving torque isdetermined to be equal to or greater than the first threshold.

With the shifting system according to the twelfth aspect, it is possibleto allow the gear shift to be performed when the driving torque is equalto or greater than the first threshold, thereby improving shiftperformance.

In accordance with a thirteenth aspect of the present invention, theshifting system according to the eleventh or twelfth aspect isconfigured in a manner such that the controller is configured to refrainfrom outputting the command signal to the shift mechanism if the drivingtorque is determined to be less than the first threshold.

With the shifting system according to the thirteenth aspect, it ispossible to prevent the gear shift from being performed when the drivingtorque is less than the first threshold, thereby improving shiftperformance.

In accordance with a fourteenth aspect of the present invention, theshifting system according to any one of the eleventh through thirteenthaspects is configured in a manner such that the controller is configuredto receive a cadence of the human-powered vehicle from at least onesensor.

With the shifting system according to the fourteenth aspect, it ispossible to it is possible to control the gear shift to be performed inview of the cadence, thereby improving shift performance.

In accordance with a fifteenth aspect of the present invention, theshifting system according to the fourteenth aspect is configured in amanner such that the controller is configured to determine a permittedshift timing based on the driving torque and the cadence.

With the shifting system according to the fifteenth aspect, it ispossible to it is possible to restrict the gear shift to be performedduring the permitted shift timing, thereby improving shift performance.

In accordance with a sixteenth aspect of the present invention, theshifting system according to the fifteenth aspect is configured in amanner such that the permitted shift timing includes a first timinginterval that has a first start and a first end. The controller isconfigured to output a command signal for the gear shift to the shiftmechanism if a current timing is between the first start and the firstend of the first timing interval.

With the shifting system according to the sixteenth aspect, it ispossible to allow the gear shift to be performed during the first timinginterval, thereby improving shift performance.

In accordance with a seventeenth aspect of the present invention, theshifting system according to the sixteenth aspect is configured in amanner such that the first start of the first timing interval is atiming at which the driving torque is detected to reach the firstthreshold as the driving torque is rising in a pedaling cycle, and thefirst end of the first timing interval is a timing at which the drivingtorque is detected to reach a second threshold as the driving torque isrising in the pedaling cycle. The second threshold is greater than thefirst threshold.

With the shifting system according to the seventeenth aspect, it ispossible to set the timing interval to begin and end at an appropriatethreshold based on whether the driving torque is rising or falling.

In accordance with an eighteenth aspect of the present invention, theshifting system according to the sixteenth aspect is configured in amanner such that the permitted shift timing includes a second timinginterval that has a second start and a second end. The controller isconfigured to control the shift mechanism to perform the gear shift byoutputting the command signal for the gear shift to the shift mechanismif the current timing is between the second start and the second end ofthe second timing interval.

With the shifting system according to the eighteenth aspect, it ispossible to allow the gear shift to be performed during a second timinginterval, in addition to the first timing interval, thereby allowingdifferent timing intervals to be used for different correspondingcircumstances.

In accordance with a nineteenth aspect of the present invention, theshifting system according to the eighteenth aspect is configured in amanner such that the second start of the second timing interval is atiming at which the driving torque is detected to reach the secondthreshold as the driving torque is falling in the pedaling cycle, andthe second end of the second timing interval is a timing at which thedriving torque is detected to reach the first threshold as the drivingtorque is falling in the pedaling cycle.

With the shifting system according to the nineteenth aspect, it ispossible to set the timing interval to begin and end at an appropriatethreshold based on whether the driving torque is rising or falling.

In accordance with a twentieth aspect of the present invention, theshifting system according to any one of the eleventh to nineteenthaspects is configured in a manner such that the driving torque includesan assist.

With the shifting system according to the twentieth aspect, it ispossible to implement the shifting system with a pedelec.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure. The term“small and/or light vehicle,” as used herein, refers to electric andnon-electric vehicles regardless of the number of their wheels, but doesnot include four-wheeled vehicles having an internal combustion engineas a power source for driving the wheels, or four-wheeled electricvehicles that require a license to operate on public roads.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings.

FIG. 1 is a right side elevation view of an example human-poweredvehicle incorporating a shifting system according to the presentdisclosure.

FIG. 2 is a schematic diagram of the shifting system.

FIG. 3 is a chart illustrating an example of driving torque over timefor one pedal of the human-powered vehicle.

FIG. 4 is a flowchart of a control method performed by the shiftingsystem.

FIG. 5 is a partial front view of an exemplary derailleur of theshifting system.

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings, wherein like reference numerals designate corresponding oridentical elements throughout the various drawings. It will be apparentto those skilled in the art from this disclosure that the followingdescriptions of the embodiments are provided for illustration only andnot for the purpose of limiting the invention as defined by the appendedclaims and their equivalents.

Referring initially to FIG. 1 , an exemplary human-powered vehicle 1having a shifting system 10 in accordance with at least one disclosedembodiment of the present invention is shown. The human-powered vehicle1 is, for example, a bicycle such as a road bicycle, a mountain bicycle,a cyclocross bicycle, a trekking bicycle, a city bicycle, or a pedelec.The following directional terms “front,” “rear,” “forward,” “rearward,”“left,” “right,” “transverse,” “upward,” and “downward,” as well as anyother similar directional terms, refer to those directions which aredetermined on the basis of a rider sitting upright on a saddle of thehuman-powered vehicle 1 while facing a handlebar, for example.

Continuing with FIG. 1 , the human-powered vehicle 1 includes a frame 2,a rear wheel 3, a front fork 4, a front wheel 5, and a crank assembly 6.The rear wheel 3 is rotatably attached to the frame 2. The front wheel 5is rotatably attached to the front fork 5. The crank assembly 6 includesa pair of crank arms 6A, a crank axle 6B, and a pair of pedals 6C. Thepair of crank arms 6A are mounted on either side of the frame 2 at 180degrees from one another and are connected by the crank axle 6B. Thepair of pedals 6C on either side of the human-powered vehicle 1 areattached to corresponding crank arms 6A. The human-powered vehicle 1 ofthe present embodiment is driven by a chain drive transmission systemthat includes a bicycle chain 7, a rear sprocket assembly 8, and a frontsprocket assembly 9. The rear sprocket assembly 8 is relativelyrotatably mounted to a hub assembly of the rear wheel 3. The rearsprocket assembly 8 includes a plurality of rear sprockets 8A. The frontsprocket assembly 9 is attached to the crank assembly 6. The frontsprocket assembly 9 includes a plurality of front sprockets 9A. Thebicycle chain 7 is engaged with one of the rear sprockets 8A of the rearsprocket assembly 8 and one of the front sprockets 9A of the frontsprocket assembly 9. A driving torque applied to the pedals 6C istransferred to the crank arms 6A, which rotate the crank axle 6B and theone of the front sprockets 9A. As the front sprocket assembly 9 rotates,the bicycle chain 7 is driven around one of the front sprockets 9A andtransmits power to the rear wheel 3 through the one of the rearsprockets 8A to propel the human-powered vehicle 1. To shift the chainbetween any of the front sprockets 9A or between any of the rearsprockets 8A, a shifting system 10 of the present invention may beemployed. Other components of the human-powered vehicle 1 may beconventional and detailed description thereof is therefore omitted.

FIG. 2 is a schematic diagram of the shifting system 10 for thehuman-powered vehicle 1. As shown, the shifting system 10 includes acontroller 12. The controller 12 may include a processor 14 and memory16 configured to hold instructions executable by the processor toperform the various functions of the controller 12. The controller 12may further include a battery 18 to provide electrical power andcommunication lines to one or more other devices described below. Thecommunication lines may be wired or wireless. While the controller 12 isillustrated in FIG. 1 as being mounted on the frame 2 of the vehicle 1,other suitable locations may be adopted, such as on or near the front orrear sprocket assembly 8 or 9, integrated with a drive assist unit, onthe handlebars, etc.

The controller 12 may be configured to receive a driving torque τ and acadence C of the human-powered vehicle 1 from at least one sensor. Theat least one sensor may be one or more of, for example, a pedal sensor20A configured to measure the driving torque τ applied to the pedals 6Cby the rider's foot and a crank sensor 20B configured to monitor whenthe crank arms 6A passes a point along a pedaling cycle, from which thecadence C is measured. In some cases, the sensors 20A, 20B may becombined to a single component which senses both the driving torque τand the cadence C. In the case of where the human-powered vehicle 1 isthe pedelec, the driving torque τ may be wholly or partially provided bya driving assist motor. That is, the driving torque τ may be, orinclude, an assist torque.

The controller 12 may be configured to determine a permitted shifttiming t_(P) based on the driving torque τ and the cadence C. Further,the controller 12 may be configured to control a shift mechanism 22 toperform a gear shift during the permitted shift timing t_(P). Thus, thepermitted shift timing t_(P) may be a torque- and cadence-dependent timeat which performance of the gear shift will not result in shift shock,or will result in acceptably low shift shock. Accordingly, thecontroller 12 may be configured to output a command signal 24 for thegear shift to the shift mechanism 22 if a current timing t is in thepermitted shift timing t_(P). In contrast, the controller 12 may beconfigured to refrain from outputting the command signal 24 to the shiftmechanism 22 if the current timing t is outside the permitted shifttiming t_(P).

FIG. 3 is a chart illustrating an example of driving torque τ over timefor one pedal 6C of the human-powered vehicle 1. Three cycles of thepedal 6C, for example, the right pedal 6C, are shown. It will beappreciated that one or both of the pedals 6C may have the sensor 20A,20B. As a chart of the left pedal 6C would typically look nearlyidentical to the chart shown in FIG. 3 , but out of phase by 180°, onlyone chart is provided by way of example.

Using the middle cycle as an example, the permitted shift timing t_(P)may include a first timing interval t₁ that has a first start t_(S1) anda first end t_(E1). As can be seen, the first timing interval t₁ lieswithin a high stability shifting zone where shift shock is absent orminimal. Thus, the controller 12 may be configured to output the commandsignal 24 for the gear shift to the shift mechanism 22 if the currenttiming t is between the first start t_(S1) and the first end t_(E1) ofthe first timing interval t₁. Here, the first start t_(S1) of the firsttiming interval t₁ may be a timing at which the driving torque τ isdetected to reach a first threshold as the driving torque τ is rising ina pedaling cycle. Further, the first end t_(E1) of the first timinginterval t₁ may be a timing at which the driving torque τ is detected toreach a second threshold as the driving torque τ is rising in thepedaling cycle. The first threshold may be predetermined and stored inthe memory, and the various timing intervals may be determined fromrecent sensor data such as the driving torque τ correlated withtimestamps. In this example, the second threshold is greater than thefirst threshold because the driving torque τ continues to rise from thefirst threshold to the second threshold.

In addition, the permitted shift timing t_(P) may include a secondtiming interval t₂ that has a second start t_(S2) and a second endt_(E2). As with the first timing interval t₁, the controller 12 may beconfigured to control the shift mechanism 22 to perform the gear shiftby outputting the command signal 24 for the gear shift to the shiftmechanism 22 if the current timing t is between the second start t_(S2)and the second end t_(E2) of the second timing interval t₂. As opposedto the first timing interval t₁ when the driving torque is rising, thesecond start t_(S2) of the second timing interval t₂ may be a timing atwhich the driving torque is detected to reach the second threshold asthe driving torque τ is falling in the pedaling cycle. Similarly, thesecond end t_(E2) of the second timing interval t₂ may be a timing atwhich the driving torque τ is detected to reach the first threshold asthe driving torque τ is falling in the pedaling cycle.

Returning to FIG. 2 , the controller 12 may be configured to receive aninput 26 regarding the gear shift. The shifting system 10 may comprise amanual input device 28, the controller 12 being configured to receivethe shift input 26 requesting the gear shift via the manual input device28. Alternatively, an automatic shifting system may be configured toperform the gear shift without receiving the shift input 26 from themanual input device 28. However, in the case where the rider actuatesthe manual input device 28, the controller 12 may be configured totemporarily hold the command signal 24 in the memory 16 of thecontroller 12 until the permitted shift timing t_(P) is reached if theinput 26 is received at an input timing that is outside the permittedshift timing t_(P).

FIG. 4 is a flowchart of a control method 400 performed by the shiftingsystem 10. As discussed above, at step S2, the controller 12 may receivethe shift input 26. At step S4, the controller 12 may receive thecadence C and/or the driving torque T. Further, the permitted shifttiming t_(P) may include the first timing interval t₁ that has the firststart t_(S1) and the first end t_(E1). Generally, at step S6, thecontroller 12 may be configured to control the shift mechanism 22 toperform the gear shift by determining at least one of an estimatedtravel distance D_(T) (see FIG. 5 ) of the shift mechanism 22 andestimated travel speed of the shift mechanism 22 for performing the gearshift. However, the gear shift may be one of a plurality of gear shifts,the estimated travel distance D_(T) may be one of a plurality ofestimated travel distances D_(T), and the estimated travel speed may beone of a plurality of estimated travel speeds. In this case, thecontroller 12 may be configured to store a map 34 that maps each of theplurality of gear shifts to an associated one of the plurality ofestimated travel distances D_(T) and one of the plurality of estimatedtravel speeds in the memory 16. In some cases, according to step S8, theestimated travel speed may be calculated based on the cadence and thetravel distance D_(T).

Then, at step S10, the controller 12 may calculate an estimated durationof time t_(SHIFT) that is required for performing the gear shift basedon at least one of the estimated travel distance D_(T) and the estimatedtravel speed. By reading the map 34 in step S6 above, the controller 12may be configured to determine the at least one of the estimated traveldistance D_(T) and the estimated travel speed for performing the gearshift at least in part by using the map 34 to identify at least one ofthe estimated travel distance D_(T) and the estimated travel speedassociated with the gear shift.

At step S12, the controller 12 may determine whether the driving torqueτ is falling or rising in the pedaling cycle. If the driving torque τ isrising, the controller 12 may determine at step S14 if the timet_(SHIFT) to perform the gear shift added to the current time t isgreater than the first start t_(S1). If not, then the command signal 24is held in the memory 16 at step S16 and the step S14 is repeated later.If the result of step S14 is YES, then at step S18, the controller 12may determine if the time t_(SHIFT) to perform the gear shift added tothe current time t is less than the first end t_(E1). If not, then thecommand signal 24 is held in the memory 16 at step S16.

Similarly for the case in which the driving torque τ is rising, if thecontroller 12 determines that the driving torque τ is falling at stepS12, then at step S20, the controller 12 may determine if the timet_(SHIFT) to perform the gear shift added to the current time t isgreater than the second start t_(S2). If not, then the command signal 24is held in the memory 16 at step S22 and the step S20 is repeated later.If the result of step S20 is YES, then at step S24, the controller 12may determine if the time t_(SHIFT) to perform the gear shift added tothe current time t is less than the second end t_(E2). If not, then thecommand signal 24 is held in the memory 16 at step S22.

Alternatively to each step where the command signal 24 is held in thememory 16, the command signal 24 may not be outputted or stored, and thegear shift may instead be prevented from being performed until a newgear shift is requested by either the rider or the automatedinstructions of a drive assist unit. Further alternatively, thecontroller 12 may be configured to output a preliminary signal (seeoptional steps S17 and S23 in FIG. 4 ) to the shift mechanism 22 toperform a preparation for the gear shift before outputting the commandsignal 24 temporarily held in the memory 16. For example, a chain guide32A of a rear derailleur 30A (see FIG. 5 ) may be moved toward a targetchain ring in anticipation of the gear shift without actually performingthe gear shift. Finally, once the controller 12 determines that the gearshift can be commenced after the first start t_(S1) of the first timinginterval t₁ and completed prior to the first end t_(E1) of the firsttiming interval t₁ (YES at step S18 or step S24), the controller 12 mayoutput the command signal 24 to the shift mechanism 22 based on thedetermination result at step S26.

As discussed above, the shifting system 10 for the human-powered vehicle1 may comprise the controller 12 configured to receive the cadence C ofthe human-powered vehicle 1 from the at least one sensor 20A, 20B. Inaddition, the controller 12 may be configured to control the shiftmechanism 22 to perform the gear shift by outputting the command signal24 for the gear shift if the cadence C is determined to be within apermitted cadence range. The permitted cadence range may bepredetermined and stored in the memory 16 in a map similar to the map34. Further, the permitted cadence range may be dependent on variousfactors including the driving torque τ or the particular gear shift tobe performed, for example. The controller 12 may be configured tocontrol the shift mechanism 22 by refraining from outputting the commandsignal 24 to the shift mechanism if the cadence C is determined to beoutside the permitted cadence range. In particular, the controller 12may refrain from outputting the command signal 24 if the cadence C isgreater than or equal to a first threshold, thus avoiding shiftingduring fast cycling of the chain rings 9A, 9B. Further, the controller12 may refrain from outputting the command signal 24 if the cadence C isless than or equal to a second threshold that is lower than the firstthreshold, thus avoiding shifting during slow cycling of the chain rings9A, 9B. After refraining, the controller 12 may be configured to outputthe command signal 24 if the cadence C changes to be within thepermitted cadence range, or wait until another gear shift is instructed.

In one implementation, as discussed above, the shifting system 10 forthe human-powered vehicle 1 may comprise the controller 12. Thecontroller 12 may be configured to receive the driving torque τ of thehuman-powered vehicle 1 from the at least one sensor 20A, 20B. Here, thecontroller 12 may be configured to control the shift mechanism 22 toperform the gear shift by outputting the command signal 24 for the gearshift if the driving torque τ is determined to be equal to or greaterthan a first threshold. Thus, the gear shift may be restricted to timeswhere sufficient driving torque τ is used to avoid shift shock. Further,the controller 12 may be configured to refrain from performing the gearshift if the driving torque τ is determined to be less than the firstthreshold.

Returning to FIG. 1 , the shifting system 10 may include the shiftmechanism 22 including a rear derailleur 30A having a rear chain guide32A configured for lateral movement over the estimated travel distanceD_(T) in a direction parallel to a rotational axis of the rear sprocketassembly having a plurality of rear sprockets 8A to urge the chain 7from the one of the rear sprockets 8A to the other of the rear sprockets8A in the gear shift. Alternatively or in addition, the shifting system10 may include the shift mechanism 22 including a front derailleur 30Bhaving a front chain guide 32B configured for lateral movement over theestimated travel distance D_(T) in a direction parallel to a rotationalaxis of the front gearset having a plurality of front sprockets 9A tourge the chain 7 from the one of the front sprockets 9A to the other ofthe front sprockets 9A in the gear shift. FIG. 5 is a partial front viewof an exemplary derailleur of the shifting system 10. While the rearderailleur 30A is used by way of example, the front derailleur 30B alsoincludes a respective chain guide 32B that is configured for similarlateral movement. Here, the chain guide 32A moves from one dotted lineto the other, over the estimated travel distance D_(T). The direction ofthe movement is right and left in FIG. 5 , which corresponds to arotational axis (oriented into the page) of the rear sprocket assembly 8shown in FIG. 1 .

In some implementations, the shifting system 10 may include anindication device 36, as shown in FIGS. 1 and 2 . The controller 12 maybe configured to cause the indication device 36 to indicate thepermitted shift timing t_(P) by at least one of a visual manner, anaural manner, and a haptic manner. Thus, the indication device 36 may bea speaker, display, light, and or vibration unit, for example. While theindication device 36 is illustrated attached to the handlebars of thevehicle 1, it will be appreciated that the indication device 36 may beplaced in any suitable location such as on the rider's helmet, on therider's wrist or other body part, or on the frame 2 of the vehicle 1.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, the size, shape, location, ororientation of the various components can be changed as needed and/ordesired. Components that are shown directly connected or contacting eachother can have intermediate structures disposed between them. Thefunctions of one element can be performed by two elements, and viceversa. The structures and functions of one embodiment can be adopted inanother embodiment. It is not necessary for all advantages to be presentin a particular embodiment at the same time. Every feature which isunique from the prior art, alone or in combination with other features,also should be considered a separate description of further inventionsby the applicant, including the structural and/or functional conceptsembodied by such feature(s). Thus, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

The invention claimed is:
 1. A shifting system for a human-poweredvehicle, comprising: a controller configured to: receive a cadence ofthe human-powered vehicle from at least one sensor; and control a shiftmechanism to perform a gear shift in accordance with a permitted cadencerange by outputting a signal concerning at least one of an estimatedtravel distance of the shift mechanism and an estimated travel speed ofthe shift mechanism for performing the gear shift during a permittedshift timing, wherein the permitted shift timing includes a first timinginterval, and the first timing interval has a first start and a firstend.
 2. The shifting system according to claim 1, wherein the controlleris configured to output a command signal for the gear shift to the shiftmechanism if the cadence is determined to be within the permittedcadence range.
 3. The shifting system according to claim 1, wherein thecontroller is configured to refrain from outputting a command signal tothe shift mechanism if the cadence is determined to be outside thepermitted cadence range.
 4. The shifting system according to claim 1,wherein the controller is configured to receive a driving torque of thehuman-powered vehicle from at least one sensor.
 5. The shifting systemaccording to claim 4, wherein the controller is configured to determinethe permitted shift timing based on the driving torque and the cadence.6. The shifting system according to claim 5, wherein the controller isconfigured to control the shift mechanism to perform the gear shift by:calculating an estimated duration of time that is required forperforming the gear shift based on at least one of the estimated traveldistance and the estimated travel speed; determining that the gear shiftcan be commenced after the first start of the first timing interval andcompleted prior to the first end of the first timing interval; andoutputting a command signal to the shift mechanism based on thedetermination result.
 7. The shifting system according to claim 6,wherein the estimated travel speed is calculated based on the cadenceand the travel distance.
 8. The shifting system according to claim 6,wherein the gear shift is one of a plurality of gear shifts, theestimated travel distance is one of a plurality of estimated traveldistances, and the estimated travel speed is one of a plurality ofestimated travel speeds, and the controller is configured to: store amap that maps each of the plurality of gear shifts to an associated oneof the plurality of estimated travel distances and one of the pluralityof estimated travel speeds in a memory, and determine the at least oneof the estimated travel distance and the estimated travel speed forperforming the gear shift at least in part by using the map to identifyat least one of the estimated travel distance and the estimated travelspeed associated with the gear shift.
 9. The shifting system accordingto claim 6, further comprising: the shift mechanism including a rearderailleur having a rear chain guide configured for lateral movementover the estimated travel distance in a direction parallel to therotational axis of the rear sprocket assembly having a plurality of rearsprockets to urge a chain from the one of the rear sprockets to theother of the rear sprockets in the gear shift.
 10. The shifting systemaccording to claim 6, further comprising: the shift mechanism includinga front derailleur having a front chain guide configured for lateralmovement over the estimated travel distance in a direction parallel tothe rotational axis of the front sprocket assembly having a plurality offront sprockets to urge a chain from the one of the front sprockets tothe other of the front sprockets in the gear shift.
 11. The shiftingsystem according to claim 1, wherein the gear shift is configured to becommenced after the first start of the first timing interval andcompleted prior to the first end of the first timing interval.
 12. Theshifting system according to claim 1, wherein the permitted shift timingincludes a second timing interval, the second timing interval has asecond start and a second end, and the second timing interval isdifferent from the first timing interval.
 13. A shifting system for ahuman-powered vehicle, comprising: a controller configured to: receive acadence of the human-powered vehicle from at least one sensor; andcontrol a shift mechanism to perform a gear shift in accordance with apermitted cadence range by outputting a signal concerning at least oneof an estimated travel distance of the shift mechanism and an estimatedtravel speed of the shift mechanism for performing the gear shift,wherein the controller is configured to receive a driving torque of thehuman-powered vehicle from at least one sensor, the controller isconfigured to determine a permitted shift timing based on the drivingtorque and the cadence, the permitted shift timing includes a firsttiming interval that has a first start and a first end, and thecontroller is configured to control the shift mechanism to perform thegear shift by: calculating an estimated duration of time that isrequired for performing the gear shift based on at least one of theestimated travel distance and the estimated travel speed; determiningthat the gear shift can be commenced after the first start of the firsttiming interval and completed prior to the first end of the first timinginterval; and outputting a command signal to the shift mechanism basedon the determination result.